Dataset Information

Defect-engineered epitaxial VO2±? in strain engineering of heterogeneous soft crystals.

ABSTRACT: The success of strain engineering has made a step further for the enhancement of material properties and the introduction of new physics, especially with the discovery of the critical roles of strain in the heterogeneous interface between two dissimilar materials (for example, FeSe/SrTiO3). On the other hand, the strain manipulation has been limited to chemical epitaxy and nanocomposites that, to a large extent, limit the possible material systems that can be explored. By defect engineering, we obtained, for the first time, dense three-dimensional strongly correlated VO2±? epitaxial nanoforest arrays that can be used as a novel "substrate" for dynamic strain engineering, due to its metal-insulator transition. The highly dense nanoforest is promising for the possible realization of bulk strain similar to the effect of nanocomposites. By growing single-crystalline halide perovskite CsPbBr3, a mechanically soft and emerging semiconducting material, onto the VO2±?, a heterogeneous interface is created that can entail a ~1% strain transfer upon the metal-insulator transition of VO2±?. This strain is large enough to trigger a structural phase transition featured by PbX6 octahedral tilting along with a modification of the photoluminescence energy landscape in halide perovskite. Our findings suggest a promising strategy of dynamic strain engineering in a heterogeneous interface carrying soft and strain-sensitive semiconductors that can happen at a larger volumetric value surpassing the conventional critical thickness limit.

SUBMITTER: Wang Y

PROVIDER: S-EPMC5969812 | biostudies-other | 2018 May

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Defect-engineered epitaxial VO<sub>2±δ</sub> in strain engineering of heterogeneous soft crystals.

Wang Yiping Y Sun Xin X Chen Zhizhong Z Cai Zhonghou Z Zhou Hua H Lu Toh-Ming TM Shi Jian J

Science advances 20180525 5

The success of strain engineering has made a step further for the enhancement of material properties and the introduction of new physics, especially with the discovery of the critical roles of strain in the heterogeneous interface between two dissimilar materials (for example, FeSe/SrTiO<sub>3</sub>). On the other hand, the strain manipulation has been limited to chemical epitaxy and nanocomposites that, to a large extent, limit the possible material systems that can be explored. By defect engin ...[more]

PMID: 29806024

Similar Datasets

Project description:Framework materials at the molecular level, such as metal-organic frameworks (MOF), were recently found to exhibit exotic and counterintuitive micromechanical properties. Stimulated by host-guest interactions, these so-called soft porous crystals can display counterintuitive adsorption phenomena such as negative gas adsorption (NGA). NGA materials are bistable frameworks where the occurrence of a metastable overloaded state leads to pressure amplification upon a sudden framework contraction. How can we control activation barriers and energetics via functionalization of the molecular building blocks that dictate the frameworks' mechanical response? In this work we tune the elastic and inelastic properties of building blocks at the molecular level and analyze the mechanical response of the resulting frameworks. From a set of 11 frameworks, we demonstrate that widening of the backbone increases stiffness, while elongation of the building blocks results in a decrease in critical yield stress of buckling. We further functionalize the backbone by incorporation of sp3 hybridized carbon atoms to soften the molecular building blocks, or stiffen them with sp2 and sp carbons. Computational modeling shows how these modifications of the building blocks tune the activation barriers within the energy landscape of the guest-free bistable frameworks. Only frameworks with free energy barriers in the range of 800 to 1100 kJ mol-1 per unit cell, and moderate yield stress of 0.6 to 1.2 nN for single ligand buckling, exhibit adsorption-induced contraction and negative gas adsorption. Advanced experimental in situ methodologies give detailed insights into the structural transitions and the adsorption behavior. The new framework DUT-160 shows the highest magnitude of NGA ever observed for nitrogen adsorption at 77 K. Our computational and experimental analysis of the energetics and mechanical response functions of porous frameworks is an important step towards tuning activation barriers in dynamic framework materials and provides critical design principles for molecular building blocks leading to pressure amplifying materials.

Dataset Information

Defect-engineered epitaxial VO2±? in strain engineering of heterogeneous soft crystals.

Publications

Defect-engineered epitaxial VO<sub>2±δ</sub> in strain engineering of heterogeneous soft crystals.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets